Evaluation of Novel Dynamically Variable Electronic Delay Lines for Ultrasonic Imaging

Abstract

Phased array systems for ultrasonic imaging typically use analog delay lines to steer the receiver directivity pattern and, in some instances, to implement dynamic zoom focusing as well. Previously used schemes consisting of a binary sequence of switched analog delays result in portions of signals being inserted out of sequence, a process which leads to image artifacts. Furthermore, the longer lumped constant delay lines used in the sequence are bulky, expensive, and introduce insertion losses and phase distortion.